1. Field of the Invention
The present invention relates to a method of sequence control, and more particularly to a method of sequentially controlling a production system having various control equipment, such as a material supply unit, heating unit and so on, under predetermined control conditions.
2. Description of the Prior Art
A sequence control is used for controlling various operation equipment provided in a production plant to enable and disable the respective equipment in a predetermined sequence.
There has been proposed a sequence control method in Japanese Patent Publication KOKAI NO. 59-125403.
The method is directed to a sequence control method for use in a batch production process. In this method, there are provided two kinds of sequence control programs consisting of one or more so called equipment sequences for controlling each equipment provided in the production system and one or more so called process sequences which are combination of a plurality of equipment sequences. A plurality of the process sequences are assembled in a series of sequence control programs in a time divisional manner, in other words, serially by a batch sequence for performing a production system. In this method, each of the equipment is initialized at the time just when the respective process starts. The batch sequence puts provisional control numerical values in the sequence control program and practical numerical value are placed in the sequence control program when the program is actually started.
In the conventional sequence control method, it is necessary to design the sequence control programs for all of the production processes of all of the products to be produced. Also, it is difficult to design the sequence control program without specific experience about the design technique of the sequence control and the installation of the production plants.